The invention is directed to an analytical system for the determination of a component of a fluid with a test carrier, which has at least one test field, and an evaluating instrument for the measurement of a change in the test field that is characteristic of the concentration of the component to be determined. A temperature conditioner is provided to heat the test field to an elevated temperature before the evaluation.
For the qualitative or quantitative analytical determination of fluids, especially body fluids such as blood and urine, so-called carrier-bound tests are being used more and more. For these tests, reagents are embedded in the dry state in appropriate test fields of a test carrier. When the test field is brought into contact with the sample, the reaction of sample and reagent leads to a measurable change in the test field.
Evaluating instruments are used to measure the change in the test field caused by the reaction. This change generally consists of a color change, the reflection of which is measured photometrically by the instrument. However test carriers working on the basis of other physical quantities, such as the fluorescence, are also known.
The test carriers frequently are constructed as test strips, in which one or several test fields are applied to a longitudinal carrier of synthetic resin material. However, test carriers in the form of square or rectangular platelets are also known. The evaluating instruments usually are matched to test carriers of a particular type from a particular manufacturer. The test carrier and evaluating instrument form an analytical system.
It is frequently desirable to heat test fields to an elevated temperature during the reaction. This is generally accomplished by pressing the test field side or even the reverse side of the test carrier against a heated metal surface. Alternatively, incubation chambers having an elevated temperature are used in which the test carriers remain in the time period between the application of the sample and the evaluation. Frequently, an acceleration of the reaction and an increase in detection sensitivity can be achieved by heating.
Previously used methods, however, are not satisfactory in every respect. Above all, the heating is very slow. Moreover, it is not possible to heat narrow spatial areas selectively, as is particularly desirable for multiple-test strips for urine analysis. The various test fields of such a multiple test strip frequently work optimally at different temperatures. Considerable difficulties have been encountered in modifying the chemical composition of test fields so that all could be evaluated at the same temperature. It would be substantially simpler if it were possible to heat the individual test fields selectively and rapidly, without affecting the adjacent test fields.